1. Field of the Invention
This invention relates to devices and methods for blocking or plugging an oil well, or similar well, when required to extinguish fires, contain saltwater intrusion, and the like.
2. Description of the Prior Art
Most existing devices for plugging oil wells rely on either plugging the top of the well or forcing a material, such as concrete, down through the hole to the desired depth at the time plugging the hole becomes necessary. The first of these approaches is not effective in many instances because it is necessary to place the blockage much lower in the hole. The second method is extremely difficult especially under a "blowout" condition. Applicant's prior invention, U.S. Pat. No. 3,726,340 dated Apr. 10, 1973, provides an apparatus for the generation of a polyurethane type foam at a desired depth in the well. The present invention discloses an apparatus and method for utilizing such devices by preplacing them at a predetermined depth in the well.